How to achieve an effect like this?

Here is a screenshots of an UE3 game called Alice: Madness Returns.
(Image is too bog for forum post)

My question is, how to achieve something like this? Like the whole scene is in black and white, and only certain elements retain their color.
I’ve seen this effect in DmC Devil May Cry too.
I’m not expert, but I suppose I need to create a custom post-process for this, I just don’t know how and where to start.
Thanks in advance!

I would approach it with custom LUT

Thank you very much, I’ve found docs related to LUT, and it’s not exactly what I want, but it’ll do. Thanks

This is probably not the most effective way to do it, but while making the textures, you could just have only the things you want, to have color

One way of doing it is keeping higine of style, i mean it’s just a visual style if you keep everything white black and allow only reds in assets eveything will look like that

But if you want to enforce it 100%, you can do anything with Post Processing. Post Processing is shader and in UE4 material is a shader, that why you can make post processing material which edit the code:

You just need to create material which will leave out just red by computation, computing hue will be essential here: